Domestic water heating and gas supply system



Oct. 5, 1937. W- THRALL 2,094,908

DOMESTIC WATER HEATING AND GAS SUPPLY SYSTEM Oct. 5, 1937. w. l. THRALL2,094,908l

DOMESTIC WATER HEATING AND GS SUPPLY SYSTEM Filed OGL 26, 19:54 3Sheets-Sheei E y A /M J//W /02 IZ N/ 17u/enfer'.

wai; er I Trail Oct. v5, 1937. W. THRALL DOMESTIC WATER HEATING AND GASSUPPLY SYSTEM Filed Oct. 26, 1934 3 Sheets-Sheet 3 5W N/ @y 441V/ @Ewar/[677 I. Fira/ Patented Oct. 5, 1937v DOMESTIC WATER HEATING AND GASSUPPLY SYSTEM Walter I. Thrall, South Pasadena, Calif.

Application October 26,

11 Claims.

This invention deals generally with combined water heating and gasgenerating systems, particularly for purposes of domestic supply,utilizing as fuel liquefied volatile petroleum or natural gas fractions.'Iypical of such fuels is that commonly and hereinafter referred to asbutane, which ordinarily includes along with normal butane, someiso-butane and propane. Butane is commercially distributed in highpressure drums Within which the fuel is maintained in liquid phase undera pressure in the neighborhood of 60 lbs. per sq. in. at normalatmospheric temperatures. At present, this fuel finds one of its chiefuses for domestic purposes in those districts where natural ormanufactured gas is not available,'or where their cost is excessivelyhigh.

One of my chief objects is to provide a'water heating system that isspecially designed to opcrate on butane or other fuel that maybe gasiedin the system, and which has all the features of convenience and safetythat characterize the usual automatic gas fueled Water heating systems.In most instances I prefer to provide in conjunction with the waterheating system, a domestic gas supply system for household lighting,stoves, heaters and the like.

'I'he present system includes, generally speaking, a water containingtank or shell of suitable form, heated by a burner which receives fuelthrough a line connecting with a supply source. The liquid fuel isvaporized by a heater placed in the fuel line and supplied with heatresulting from combustion of the gas at the burner. While the inventionbroadly contemplates the use of any suitable fuel vaporizer having theWater heating burner as its ultimate heat supply source, I prefer to usea heater which vaporizes the fuel by.transference of heat from the wateritself, by reason of the more uniform temperature of the water. In thetypical form hereinafter described in detail, the heater is placedwithin the tank and in direct contact with the hot water.

I reduce the generated gas pressure by a regulator placed in the linebetween the heater and the burner, and feed the gaseous fuel to theburner at a pressure slightly above atmospheric. Where the system isalso to be used for gasifying the fuel for supplying domesticappliances, a gas main is connected with the low pressure side of theregulator, the gas being supplied to the main at constant pressure andat rates sufficient to meet the requirements of domestic use.

'I'he invention' involves various additional features and objects thatmight be set out at some length, but it is believed that all these canbest 1934, serial No. v150,1.28

(ci. 15a-53) be explained without necessity for further preliminarydiscussion, by describing certain typical and illustrative forms. In thedescription to follow, reference is made to the accompanying drawings,in which: 5

Fig. 1 is a sectional view showing a typical form of water heating andgas supply system embodying the invention;

Fig. 2 is an enlarged sectional view of the fuel heater and vaporizer; v

Fig. 3 is an enlarged sectional detail of the hot water outlet controlvalve;

Fig. 4 is a fragmentary section taken on line 4-4 of Fig. 3;

Fig. 5 is an enlarged sectional detailv of the 15 liquid control valve;

Fig. 6 is a view similar to Fig.y 1, showing another form of theinvention;

Fig. 7 is an enlarged detail of the vaporizer element in Fig. 6; and 20Fig. 8 is a diagrammatic illustration of the type of valve shown in Fig.6.

Referring rst to Fig. 1, numeral I 0 indicates the fuel supply drumwithin which liquid butaneis maintained under high pressure, and fromthe 25 bottom of which the liquid fuel ows through line II to a fuelheater and vaporizer generally indicated at I2. A pressure regulator,diagrammatically indicated at I3, placed in line II be' tween the heaterI2 and supply drum I0, oper- 30 ates to reduce the fuel pressure fromsay 60 lbs. per sq. in. to in the neighborhood of 10 lbs. per sq. in.gage, although the extent of the pressure drop at this point may vary indifferent installations. Asa result of the ypressure drop, a portion ofthe liquid fuel may vaporize, cooling to a substantial extent, dependingupon .thepressure differential and surrounding temperature conditions,the fuel and vapor stream flowing through line II to the heater I 2.Water is supplied through inlet I4 to a shell I5 which may be of anysuitable shape,'though I have shown typically a cylindric tank. The tankis surrounded by a layer I 6 of heat insulating material I0 spaced at Ilfrom the tank to provide a vent space into which the hot gases fromcombustionl chamber I8 enter through ports I3 and ow upwardly into space20 between cover 2| and the top I 5a of the tank, and thence out throughopening 22. The tcp of the tank and the various hereinafter describedpipes connecting therewith, are covered by a hood 23.

If desired, a cooler generally indicated at 2l, may be placed in line II at the expansion side of pressure regulator I3. Broadly speaking,cooler 24 may be regardedas typical of any suitable mildly refrigeratedunit for cooling fluids, or in fact any other commodity for householdusage.

., As a typical example of its various possible uses,

I have shown it as a water cooler in the form of a heat insulatedcylinder having an inlet 25 Y connecting with line I4 and an outlet 21.By increasing the areas of the surfaces through which heat istransferred from the liquid in cylinder 25 to the fuel in line II, thetemperature of the liquid drawn through outlet 21 may be lowered asdesired. However, where the unit is used as a water cooler, it isusually advisable to limit the degree of refrigeration in order to avoidfreezing. This may be done simply by extending line II through thecooler cylinder without special provisions being made to increase heattransfer rates and resultant cooling capacity.

The heater I2, see Fig.- 2, comprises an elongated-cylindric shell 28depending within the water tank and having a top flange 29 clampedbetween plate 3l and a ring 3I welded to the top closure I5a of thetank. Heater shell 28 may be made of copper or any other suitablematerial having high heat conductivity. The liquid and vfuel to.- the-heater being controlled by a float operated valve generally indicatedat 33. The

valve assembly comprises a bushing 34 threaded into the inlet 32, and avalve 35 carrying a composition insert 35 which seats against the lowerend of the bushing. Fuel admitted past the valve flows downwardlythrough grooves 31 into annular space 38 between the valve operating rod33 and a surrounding tube 40, and thence into the Abottom portion of theheating chamber 4I.

Under normal conditions, for example when the water temperature withintank I5 is around 105 to 140 F., the liquid fuel entering the heatingchamber 4I will become completely vaporized as fast as it flows into thechamber by heat transferred from the water through the wall of shell 28,As a precautionary measure to prevent the accumulation of excessunvaporized fuel within the heater chamber, as might possibly resultfrom abnormally low water temperatures in the tank or faulty operationof a valve in the fuel line, I provide a float control for the fuelinlet valve 33 that operates to close the valvewhen liquid fuelaccumulating in the heater rises to a predetermined level.

'I'he oat control comprises a lever 42 pivoted at 43 to a lug 44 carriedon the lower end of pipe 45, and having a pin-and-slot connection at 45with the lower end of the valve rod 39. Float ball 45 normally rests onthe bottom of the heater shell, but as liquid fuel accumulates, thefloat rises to the illustrated position at which it engages lever 42 tokclose inlet valve 33. As the accumulated body of liquid fuel vaporizes,the float lowers to open the inlet valve and to admit more fuel to theheater. Pipe 48 is a blow-oil' line through which chamber 4I may bepurged of water, oil or other foreign substances accumulating in thebottom of the shell.

Vaporized fuel leaves the heater through an outlet 49 connecting vialine 50 with a suitable pressure regulator, diagrammatically indicatedat 5I, which operates to subject the fuel to a second pressurereduction. The burner fuel supply line 52 leads from the low pressureoutlet 5Ia of reg- A ulator 5I to a valve 53 controlled in accordance2duce the fuel pressure to aroun mostat 54. of fuel through pipe 55 tothe main burner 58. Pilot burner 51 receives fuel through line 58continuously and uniniluenced by thermostat valve 53. Should the pilotburner flame become extinguished, thermostat 59 acts in the ordinarymanner to close valve 55, thus shutting off further ilow of fuel to themain burner. The illustrated arrangement of burner supply lines andtemperatur'e responsive valves are common practice and need not be shownor described in detail.

In the usual installation, reggitor 5I will re- IIl" of water, althoughthe pressure reduction in this final stage may be adjusted to suit therequirements of any particular installation. In addition to the burnersupply line 52, a gas main 5| connects with the regulator outlet, thismain serving as a gas supply line towhich the usual gas consuminghousehold appliances may be connected. l As will be understood from theforegoing, the fuel in main 5I is Valve 53 in turn regulates the flow.

completely gasified and is supplied at uniform predetermined pressure.

It is desirable that in the event both the pilot and master burner namesbecomes extinguished, the ilow of fuel to the entire-system bediscontinued to avoid accumulation of unvaporized butane in the lines,and to forestall erratic operation resulting from fuel vaporization byconduction of atmospheric heat alone. For .this purpose I provide avalve 52 located in line II between cooler 24 and regulator I3, andoperated by the expansion and contraction of ether or other volatilefluid contained within a tube 53 disposed directly above the pilotburner. 'Ihis valve, as shown in detail in Fig. 5, comprises bodysections 54 and 55 between which a diaphragm 55 is clamped. Body section64 has a nipple 51 screwthreaded into the wall of base I5e. Ventopenings 58 pass hot gaseswithin the annular space 59 between the nippleand tube 53, into space I1. 'I'he valve body section 55 contains a valve10 carrying a composition insert 1I which is pressed against the seat 12by coil spring 13. the compression of the latter being adjustable byturning nut 14.

As previously stated, tube 53 contains a' volatile expansible iluid,andwhile the tube is being heated by the pilot ame, the iiuid remains in anexpanded condition exerting suillcient pressure against'diaphragm 55 tomove plunger 15 into engagement with valve 10 and to hold the valve openagainst the resistance of spring 13. While the valve is open, fuel flowsfrom inlet 11 through passages 18 Iand 19 to the outlet 80. Should thepilot flame become extinguished, the fluid in tube 53 cools to the pointat which its pressure against diaphragm 55 is overcome by spring 13,causing valve 10 to seat and shut off further fuel ilow through line II.It will be observed that valve 10 closes in the general direction offluid flow, in distinction to' other types of valves that close againstthe ilow. This feature is of importance in the ypresent system byreasonof the fact that the valve will under all conditions seatpositively to close off the flow, regardless of pressure and temperatureconditions existing within the fuel line II.

Hot water for domestic supply passes from tank I5 through outlet line8|, within which is installed a valve device, generally indicated at 82,which operates automatically to reduce, and in the particular formherein illustrated, (see Figs. 3 and 4) to entirely shut off the supplyfrom the tank when the water temperature drops below a predeterminedminimum. For example, the valve may be adjusted to close when the watertemperature Vfalls to around 90 F. By thus controlling the outlet ilowin accordance with the water temperature, it is assured that sumcient'heat will be available in the tank water to completely vaporiae, at therate required, the liquid fuel introduced to heater I2.

Valve 02 comprises upper and lower body sec'- tlons 02a, 02h, the latterforming a chamber 09 within which isv placed a copper Vor other.- heatconductive shell 00 having a topY ilange 05 clampedbetween the bodysections. -The bottom of shell 00 is clamped between a hanged nipple 00and the bottom wall of the body, the nipple being taken up tightly bynut 01 to prevent uid leakage into the shell. Shell 04 contains atemperature responsive element shown typically as a longitudinallyexpansible bellows 00 fixed at its upper end to body lug 09 and carryingon its lower end a rectangular yoke 90. Nipple 00 contains a pair ofspring detents 9| attached to plug 92 and adjustable as to spread byscrews 90. Detents 9| act to releasably engage a spherical knob 90depending from the bellows yoke 90, as will later appear more fully.

Yoke 90 is.attached to a vertically movable valve rod 95 extendingthrough a guide plug 96 and carryingthe valve 91. The valve is apressure balanced type operated in accordance with longitudinalexpansion and contraction of the bellows 00. The valve assemblycomprises an insert 90 threaded into the upper body section 02a andremovable for replacement or repair through bore 99 closed by removableplug |00. 'Ihe insert 90 has an upper bore |0| and a lower counterbore|02 communicating through ports |03 with an annular body channel |04.Valves |05 and |00 seating against the lower ends of bores |0| and |02,respectively, control the passage of uid from channel |00 to the outlet|01, see Fig. 4, by way of bore |0l, chamber |00 and passage |09, andthrough bore |02, chamber ||0 and port lll.

Water from the tank l0 enters chamber 03 through inlet ||2 and owsupwardly to the annular space |00 through passage H3. Heat contained inthe water circulating around shell 04 is conducted through air chamberIII to the bellows 00, causing the latter to expand or contract as thewater temperature increases or decreases. When the water temperature isbelow a predetermined minimum, the valve 91 is closed and the parts arein the positions shown in Fig. 3. As the water temperature increases,bellows 00 expands downwardly, lowering yoke 90 and opening valve 91 topermit the flow of -water through bore |0|, chamber |00 and passage |09to the outlet, and through bore |02, chamber ||0 and port ||I.

The bellows continues to expand to the point at which knob 90 reachesthe dotted line position 90a in which it is engaged by the springdetents 9|. The valve is now fully opened, with any tendency to close asa result of contraction 'of the bellows being resisted by the action ofthe detents 9|. Thus when the water temperature begins to drop Aas thehot water supply in the tank becomes depleted, valve 91 does not closeprogressively but is held fully open by the detents until apredetermined temperature drop occurs. At that point the contractiveforce of the bellows 00 becomes suihcient to release knob 94 from thedetents and to cause the valve to suddenly close. Since furtherwithdrawal of water ls thus prevented, the water temperature in thetank' returns to normal within a comaratively short time. l

In Figs. 6 to 8 I show another form of the invention which, though lastto be described, may

be regarded as a preferred embodiment. While generally similar to thepreviously described system, the variational form diiers primarily inthe elimination of certain parts in the liquid fuel feeding system, andin the provision of certain valve controls in the gas supply line. Toshorten the description, similar parts in the two forms are designatedby corresponding numerals with primes added in the variational form.

` Liquid fuel is fed to the vaporizing element I2 through line ||5 whichmay connect with any suitable supply source. In case butane is used asfuel, line ||5 may connect with the butane of a supply drum, not shown.It will be noted that in this instance the fuel is fed to the vaporizerinlet without a previous reduction in pressure, so that the pressurewithin shell ||6 will correspond to the pressure within the supply lineH5, except for whatever reduction that may take place at valve 05. Shell||0 will be made sufclently strong to withstand the vapor pressure ofthe most volatile fuels. A certain amount of pressure drop and expansionof the fuel may occur at valve 35', although not necessarily, and ifdesired the valve may be designed so that a considerable pressurereduction and corresponding expansion of the fuel will occur at thispoint.

In Fig. 7, I show a different form of mounting for the fuel vaporizingelement, having the advantage that the entire unit may be withdrawn fromthe water tank without disconnecting the inlet and outlet casting fromthe vaporizer shell. Here the upper end of shell ||6 is screwthreadedinto an annular groove I1 within casting ||0, this type of joint betweenthe shell and casting being used to resist radial expansion strains onthe shell due to high internal pressures. Casting ||0 is attached to thetop |5a' of shell l5' by bolts |9 of gasket |20 being interposed toprevent leakage from shell I5'. The liquid fuel inlet |2| and gas outlet|22 are formed as integral parts of the casting H8. In order to replaceor repair the vaporizing element, it is only necessary to remove thenuts from bolts ||9, disconnect the fuel and gas lines, and lift theunit out of the water shell.

As in the previously described form, generated gas flows through line 50to regulator 5|' and then into the gas main 0| connecting with the lowpressure `outlet of the'regulator. The low pressure gas is fed to themain burner 50' through line 55' under control of thermostat valve 53',and to pilot burner 51 through line 50'. In gas main 0|', certainautomatic shut off valves are provided in order that if for any reasonthe water temperature in shell I5 drops below that required for heatingand vaporizing the fuel at the normal rate of consumption, the supply ofgas will become automatically shut off. Other provisions are madewhereby excessive rates of gas consumption are prevented, and wherebyonce the gas supply is discontinued, manual operation is required toagain open the gas main.

A reverse acting thermostat valve |25 actuated by the usual element |20projecting into the body of water in tank I5?, operates to shut off theflow of gas through main 6| when the water temperature drops below apredetermined degree. This type of thermostat valve is common and neednot be shown in detail. A pressure responsive automatic shut oif valve|21 installed in line 0I' beyond valve |25 operates to shut oi'i! thegas' ow when the line pressure drops below a predetermined amount. Thisgeneral type of valve is also ,commonly known and used in otherinstallations, 5 and need not be described further than by referring toa diagrammatic showing in Fig. 8, which is intended merely to typifyknown valves of this character. The device is shown diagrammatically tocomprise a body having sections |28 and |28a between which is clamped adiaphragm |23 carrying a valve |30, which has a rod I 3| projectingthrough the top of the body so as to be accessible for manual operation.Valve |30 controls the flow of gas from inlet vpassage |32 to outletpassage |33, and normally is fully opened in the position shown so thatit affords no substantial restriction to gas ow between the saidpassages. An orifice disk |34 is placed in the outlet for the purpose ofrestricting the gas stream to such an extent that the maximum rateat-which gas can be used from the main 6|' will not exceed the maximumrate at which the liquid fuel can be completely gasified withinvaporizer I5.

Valve |30 normally is held open by the line pressure acting against theunder side of diaphragm i |23 and against the resistance of spring |35.IHowever, when the thermostat valve |25 closes to shut oil' the gasflow, spring |35 overcomes the resultant reduced pressure acting againstthe diaphragm and closes the valve. Thereafter, when the watertemperature in shell I5' again rises to normal, valve |25 willautomatically open the gas main up to regulator |21, but the latter willstill remain closed because of the fact that the pressure acting againstvalve `will alone be insumcient to overcome the resistance'ofiered byspring |35. The consumer then is obliged to manually raise the vai'vestem |3| to restore the 40 line pressure against the underside of thediaphragm, so that the valve will remain open to put the gas main backin service. This requirement for manual operation of a precautionarymeasure takento direct the consumers attention to the fact thatv the gasgenerating system is again in service and that all open burners not inuse should be closed.

I claim: 1. In a system of the character described, a closed watercontaining tank having an inlet, an outlet, and a top wall having anopening of smaller cross sectional size than the cross sectional area ofthe tank, means for heating the water in the tank, a liquid fuelvaporizing element comprising a hollow heat conductive shell adapted tobe inserted through said opening in the top wall of the tank andsubmersed in the water therein, means for securing said shell to the topwall of the tank, and a fuel inlet and a gas outlet connecting with thetop of said shell.

2. In a system of the character described, a closed water containingtank having an inlet, an outlet, and a top wall having an opening ofsmaller cross sectional size than the cross sectional area of the tank,means for heating the water in the tank, a liquid fuel vaporizingelement comprising a hollow heat conductive shell adapted to be insertedthrough said opening in the -top wall of the tank and submersed in thewater therein, means for detachably fastening said shell to the top wallof the tank to permit removal of the shell through said opening, and afuel inlet and a gas outlet connecting with the top of said shell.

3. In a system of the character described, a closed water containingtank having an inlet, an

outlet, and a top wall having an opening of smaller cross sectional sizethan the cross sectional f area of the tank, means for heating the waterin the tank, a' liquid fuel vaporizing element comprising a hollow heatconductive shell adapted to bel inserted through said opening in the topwall of the tank and submersed in the water therein, a head secured tosaid shell, means for fastening said head to said top wall of the tank,and a fuel inlet and a gas outlet connecting with said head.

4. In a gas generating unit, a liquid containing tank having a top wall,means for heating liquid in the tank, a fuel vaporizing elementcomprising a heat conductive shell immersed in the liquid within saidtank, a flange on the top of said shell, means for attaching said angeto the top wall of said tank, anda fuel inlet and a gas outletconnecting with the top of the shell.

5. In a gas'generating unit, a liquid containing tank having a top Wall,means for heating liquid in the tank, a fuel vaporizing elementcomprising a heat conductive shell immersed in the liquid within saidtank and including a head secured to the upper end of said shell, meansfor fastening `said shell to said top wall of the tank, and a fuel inletand a gas outlet connecting with said head.

6. In a gas generating unit, a liquid containing tank having a top Wallcontaining an opening of smaller size than the cross sectional area ofthe tank,- means for heating the liquid'in the tank, a fuel vaporizingelement comprising a hollow heat conductive shell adapted to be insertedthrough said opening in the top wall of the tank and immersed in theliquid therein, means for detachably securing said shell to the top wallof the tank to permit removal of the shell through said opening, and afuel inlet and a gas outlet connecting with the top of said shell.

'7. In a gas generating unit, aliquid containing tank having a top wallcontaining an opening of smaller size than the cross sectional area ofthe tank, means for heating the liquid in the tank, a fuel vaporizingelement comprising a hollow heat conductive shell adapted to be insertedthrough said opening in the top wall of the tank and immersed in theliquid therein, a head secured to the upper end of said shell, means fordetachably fastening said head to the top wall of the tank to permitremoval of the shell through.

said opening, and a fuel inlet and a gas outlet connecting with saidhead.

8. Ina gas generating unit, a liquid containing tank having a top wall,means for heating liquid in the tank, a fuel vaporizing elementcomprising a heat conductive shell immersed in the liquid within saidshell and supported by said top wall of the tank, a head secured to theupper end of said shell, a fuel inlet and a gas outlet connecting withsaid head, and means associated with said head for automaticallyrestricting the flow l of fuel into said shell as unvaporized fuelaccumulates therein.

9. In a systemof the character described, a closed water containing tankhaving an inlet, an outlet, and a top wall having an opening of smallercross sectional size than the cross sectional area of the tank, a liquidfuel vaporizing element comprising a hollow heat conductive shelladapted to be inserted through said opening in the top wall of the tankand submersed in the water therein, means for securing said shell to thetop wall of the tank, a fuel inlet and a gas outlet connecting with thetop of said shell, and .a burner for heating the water in said tank andsupplied with gaseous fuel from said shell.

10. In a gas generating unit, a liquid containing tank having a topWall, a fuel vaporizing element comprising a heat conductive shellimmersed in the liquid within said tank, a flange on the top of saidshell and attached to the top Wall of the tank, a. fuel inlet and a gasoutlet connecting with the top of the shell, and a burner for heatingthe water in said tank and supplied with gaseous fuel from said shell.

11. In a gas generating unit, a liquid containing tank having a topwall, a fuel vaporizing element comprising a heat conductive shellimmersed in the liquid within said tank and having a top closure, meansconnecting said shell with said top wall of the tank, a fuel inlet andan outlet connecting with said top closure of theshell, a burner forheating the liquid in said tank, and a gas supply line connecting saidburner with said fuel outlet. y

WALTER I. 'I'I-IRALI...

